The unexamined German patent application DE 101 48 155 A1 discloses an arrangement for monitoring motor starters connected to a power supply line and communicating with a control device via a control bus. Each motor starter has a measuring device for measuring the current flowing through the motor starter. A circuit breaker is provided in the power supply line and said circuit breaker is assigned a tripping device which can be controlled by the control device via the control bus as a function of the measured current.
The unexamined German patent application DE 101 02 316 A1 discloses a motor starter arrangement comprising a first electrical switching device, in particular a circuit breaker, with an electronic tripping unit and a second electrical switching device, in particular a contactor. The switching devices are connected in series for connecting or disconnecting an at least 1-phase load to/from a power source. Means of bidirectional communication between the first and second switching device are provided, the first switching device and the means of communication being implemented in such a way that tripping of the first switching device is delayed if an overload occurs, within this time the second switching device is prompted to disconnect by the communication means and, if the second switching device fails to disconnect, tripping is effected by the first switching device.
Such switching arrangements are generally known.
In the context of safety engineering, safety-relevant switching states of modules are often detected and monitored by means of switches, such as auxiliary contact switches, for example. In certain cases it is permissible to connect the switches of the modules electrically in series to form a status signaling loop. If a switch of the respective modules then opens, the electrical supply can be overridingly shut off centrally.
From the prior art it is known to wire the switches manually, in particular the auxiliary contact switches mounted on contactors for operational load switching. This approach is time-consuming and prone to error. It is also known in this context that the status signaling loop can be automatically extended by plugging modules together by means of mating connectors. In this case the “open” contacts of the last module must be connected to one another in a still electrically conducting manner.